This is my build of the R/C car as described by our host.Now fitted with ESP8266-01 WiFi module, 10A brushed ESC and a 9g servo.The motor is the same one that it's always had.Power is 8.4V, from 2x ex laptop 20 year old li-ions.The reverse side of the ESP8266 has been used to mount the 3.3V regulator, 2x 2.2K resistors and 3 pin headers for ESC and servo outputs. Weight of the receiver is 3 grams.

Yes, the schematic looks OK.Then you can follow this:http://www.roboremo.com/flashing-nodemcu-firmware-to-esp8266.htmlor use Arduino IDE with ESP8266 Addon:https://learn.sparkfun.com/tutorials/esp8266-thing-hookup-guide/installing-the-esp8266-arduino-addon

sir Admin I have an Idea..... i want to convert this servo in to Electronic Speed Controller for rear motor.. so there is Forward and Reverse like what you posted in the schematic.. but the big problem is I want to upgrade the motor using old motor like

Yes,In the video he cuts the potentiometer and connects 2 resistors instead (resistor value 2k2) so that the controller will think that the potentiometer stays always on middle value.Then you just replace the small motor with bigger one.Then connect the servo cable to signal, +5V and GND.

In my schematic the controller takes power from battery and generates +5V for the rest of the circuit.In your case, you will have to use an external +5V source.

The controller from the servo PCB may burn if the motor you connect needs too much current. In this case, you may try to use a controller from a bigger servo.

To be honest, I am not sure, how this speed controller is supposed to work. Maybe author tranqspogi can tell us a theoretical principle, how this CD4017 diagram works? Quick search in Web did not give me answers.